Blogging is futile

Rendering Markdown, Asciidoc and Friends automatically while Editing

abe+blog@deuxchevaux.org (Axel Beckert) — Sun, 10 Mar 2013 15:41:58 +0100

Partially because of Markdown being Github’s markup format of choice, I enjoy writing documents in simple markup formats more and more.

There’s though one common annoyance with these formats compared to writing plain HTML…

The Annoyance

They need to be rendered (i.e. more or less compiled) before you can view your outpourings rendered, e.g. in the web browser. So the workflow usually is:

Saving the current file in your favourite editor
Switch to terminal with commandline
Cursor up, Enter
Switch to your favourite web browser
Hit the reload button

Using a Specialized Editor with Live Preview

One choice would be to use a specific editor with live rendering. The one I know in Debian (from Wheezy on) is ReText (Debian package retext). It supports Markdown and reStructuredText.

But as with most simple GUI editors, I miss there many of the advanced editing commands possible with Emacs.

Using Emacs’ Markdown Mode

Then there is the Markdown Mode for Emacs (part of Debian’s emacs-goodies-el package), where you can get a “preview” by pressing C-c C-c p. But for some reason this takes several seconds, opens a new buffer and window with the rendered HTML code and then starts (hardcoded) Firefox (which is not my preferred web browser). And if you do that a second time without closing Firefox first, it won’t just reload the file but will open a new tab. You might think that just hitting reload should suffice. But no, the new tab has a different file name, so reload doesn’t help. Additionally it may not use my preferred Markdown implementation. Meh.

Well, I probably could fix all those issues with Markdown Mode, it’s only Emacs Lisp. Heck, the called command is even configurable. But fixing at least four issues to fix one workflow annoyance? Maybe some other time, but not as long there are other nice choices…

Using inotifywait to Render on Write

So everytime you save the currently edited file, you immediately want to rerender the same HTML file from it. This can be easily automated by using Linux’ inotify kernel subsystem which notices changes to the filesystem, and reports those to applications which ask for it.

One such tool is inotifywait which can either output all or just specific events, or just exit if the first requested event occurs. With the latter it’s easy to write a while loop on the commandline which regenerates a file after every write access. I use either Pandoc or Asciidoc for that since both generate full HTML pages including header and footer, but you can use that also with Markdown to render just the HTML body. Most browsers render it correctly anyway:

while inotifywait -q -e modify index.md; do pandoc -s -f markdown -t html -o index.html index.md; done
while inotifywait -q -e modify index.txt; do asciidoc index.txt; done
while inotifywait -q -e modify index.md; do markdown index.md > index.html; done

This solution is even editor- and build-system-agnostic (But not operating-system-agnostic.)

inotifywait is part of inotify-tools, a useful set of commandline tools to interface with inotify. They’re packaged in Debian as inotify-tools, too.

Using mdpress for Markdown plus Impress.js based Slides

The ruby-written mdpress is a special case of the previous case. It’s a commandline tool to convert Markdown into Impress.js based slide shows and it has an option named --automatic which causes it to keep running and automatically update the presentation as soon as changes are made to the Markdown file.

mdpress is not yet in Debian, but there’s an ITP for it and Impress.js itself recently entered Debian as libjs-impress. Nevertheless, two dependencies (highlight.js, ITP‘ed, ruby-launchy, ITP‘ed) are still missing in Debian.

Illegal attempt to re-initialise SSL for server (theoretically shouldn't happen!)

abe+blog@deuxchevaux.org (Axel Beckert) — Tue, 10 Jan 2012 02:52:07 +0100

After dist-upgrading my main Hetzner server from Lenny to Squeeze, Apache failed to come up, barfing the following error message in the alphabetically last defined and enabled virtual host’s error log:

[error] Illegal attempt to re-initialise SSL for server (theoretically shouldn't happen!)

Well this is not theory but the real world and it did happen — and it took me a while to find out what was wrong with the configuration despite it worked with Lenny’s Apache version.

To avoid that others have to search as long as I had to, here’s the solution:

Look at all enabled sites, pick out those which have a VirtualHost on port 443 defined and verify that all these VirtualHost containers do have their own “SSLEngine On” statement. If at least one is missing, you’ll run into the above mentioned error message.

And it won’t necessarily show up in the error log of those VirtualHosts which are missing the statement but only in the last VirtualHost (or the last VirtualHost on port 443).

To find the relevant site files, I used the following one-liner:

grep -lE 'VirtualHost.*443' sites-enabled/*[^~] | \
  xargs grep -ci "SSLEngine On" | \
  grep :0

Should work for all sites which have defined just one VirtualHost on port 443 per file.

I suspect that the raise of SNI made Apache’s SSL implementation more picky with regards to VirtualHosts.

Oh, and kudos to this comment to an article on Debian-Administration.org because it finally pointed me in the right direction. :-)

Conkeror in the Debian NEW queue

abe+blog@deuxchevaux.org (Axel Beckert) — Thu, 27 Oct 2011 22:57:54 +0200

I already mentioned a few times in the blog that I’m working on a Debian package of the Conkeror web browser. And now, after a lot of fine-tuning (and I still further new ideas how to improve the package ;-) Conkeror is finally in the NEW queue and hopefully will hit unstable in a few days. (Update Thursday, 03-Jul-2008, 18:13 CEST: The package has been accepted by Jörg and should be included on most architectures in tonight’s updates.)

Those who could hardly await it can fetch Conkeror .debs from http://noone.org/debian/. The conkeror package itself is a non-architecture specific package (but needs xulrunner-1.9 to be available), and its small C-written helper program spawn-process-helper is available as package conkeror-spawn-process-helper for i386, amd64, sparc, alpha, powerpc, kfreebsd-i386 and kfreebsd-amd64. There are no backported packages for Etch available, though, since I don’t know of anyone yet, who has successfully backported xulrunner-1.9 to Etch.

Interestingly the interest in Conkeror seems to have risen in the Debian community independently of its Debian packaging. Luca Capello, who sponsored the upload of my Conkeror package, pointed me to two blog post on Planet Debian, written by people being fed up with Firefox 3 already and are looking for a more lean, but still Gecko based web browser: Decklin Foster is fed up with Firefox’ -eh- Iceweasel’s arrogance and MJ Ray is fed up with Firefox 3 and its SSL problems.

Since my previously favourited Gecko based web browser Kazehakase never became really stable but instead became slow and leaking memory (and therefore not much better than Firefox 2), I can imagine that it’s no more an candidate for people seaking for a lean and fast web browser.

Conkeror has some “strange” concepts of which the primary one is that it looks and feels like Emacs:

The current location is shown in a status bar below the website, where Emacs usually shows buffer names. All input, even entering new URLs to go to, is done via the mini-buffer, an input line below the status bar.
Instead of tabs it uses Emacs’ concept of buffers. So no tab bar clutter and though easy access to all currently open pages.
It has no buttons, menu-bar or such. And except the status bar and mini-buffer, it uses the whole size of the window for the displayed web page. This is the main reason why I prefer Conkeror on the 7” EeePC: I don’t want to waste any pixels for buttons or menu bars and still have a fully functional web browser.
It of course has Emacs alike keybindings (with a slight touch of Lynx). While this may seem awkward for the vi world (Hey, they have the vimperator^*, also in Debian since a few days!), as an Emacs user you just have to remember that you web browser now also expects to be treated like an Emacs. It just works:

C-x C-c
Exit Emacs -eh- Conkeror

C-x C-f
Open File -eh- web page in new buffer

C-x C-b
Change to some other tab -eh- buffer

C-x C-v
Replace web page in this buffer and use the current URL as start for entering the new one

C-x 5 2
Open new frame -eh- window

C-x 5 0
Close current frame -eh- window

C-x k
Close tab, -eh- kill buffer

C-h i
Documentation

C-s
Incremental search forward

C-r
Incremental search backward

C-g
Stop

l
Go back (Think info-mode)

g
Go to (Open web page in this buffer)

(Hehe, I like the faces of vi users having read these keybindings and now wondering how to remember them. SCNR. Well, sometimes vi key bindings are a mystery to me, too. :-)
There are of course many more and nearly all are the same as in Emacs, even the universal argument C-u and the M-x command-line are there. E.g. C-u g lets you open a web page in a new buffer, too.
Conkeror also has very promising concept for following and copying links with the keyboard only. Opera is very inefficient here since you have to jump from link to link to get to the one you want. In Conkeror you just press f for following or c for copying links and then all links on the currently shown part of the page show a small number attached to it. Then you just enter the number (and additionally press enter if the number is ambigous) and the link is either opened or copied to the clipboard.
A funny anecdote about how this concept grew over the time: Early versions of Conkeror (back in the days when it just was a Firefox externsion as vimperator) numbered all links on the page, not only the visible ones. On large pages with many links or buttons (e.g. my blog ;-), this took minutes to complete. The idea to just number the visible links is so simple and important – but someone first needed to have it. :-)

Footnotes

*) I just noticed that there is now also muttator, making Thunderbird look and behave like vim (and probably also mutt), too. Wonder into which e-mail client the Emacs community will convert Thunderbird. GNUS? RMAIL? VM? Wanderslust? What will it be called? Wunderbird? Thunderslust? (SCNRE ;-)

Daily Snapshot .debs of Conkeror

abe+blog@deuxchevaux.org (Axel Beckert) — Thu, 27 Oct 2011 22:57:51 +0200

Keeping track with packaging software which is under heavy development can be time-consuming. I noticed this while packaging Conkeror, because there was quite a demand for up-to-date packages, especially from upstream themself.

So recently on the IRC channel #conkeror the idea of automatically built Debian packages came up. After a few hours of experimenting and a few days of steadily optimizing, I can proudly present daily built snapshot packages of Conkeror for currently Lenny and Sid, ready to be included in your sources.list:

deb     http://noone.org/conkeror-nightly-debs lenny main
deb-src http://noone.org/conkeror-nightly-debs lenny main

deb     http://noone.org/conkeror-nightly-debs sid main
deb-src http://noone.org/conkeror-nightly-debs sid main

The binary package conkeror-spawn-process-helper is currently only built for the i386 architecture, but other architectures may follow.

The packages probably work also on any other Debian based distribution (e.g. Ubuntu) which includes XULRunner version 1.9.

Surely they are not of the usual Debian quality, but they should do it for staying up-to-date with the Conkeror development just by using your favourite APT frontend.

The script which generates those packages is also available in the Conkeror git repository at repo.or.cz.

The APTable archive is generated with reprepro. Packages and the repository are signed with the passphrase-less GnuPG key 373B76B4 which is used only for the Conkeror nightly builds. (If anyone knows a better solution for automatic builds than a passphrase-less key, please tell me. :-)

P.S.: I really like the new keybindings “<<”, “>>” and “G”. :-)

The World without a sage web browser? — or — Why Firefox sucks

abe+blog@deuxchevaux.org (Axel Beckert) — Thu, 27 Oct 2011 22:57:04 +0200

Although I read our Debian’s Joey’s blog posting about not being able to produce Mozilla security updates for Debian, only now, after reading about other Debian’s Joey’s try to fix a security hole in Debian’s Mozilla Firefox, I see how asshole-like the Mozilla Foundation’s security policy looks to Linux (and maybe other operating system’s) distributions, who favour stableness over feature richness.

As many know (or at least were forced to know ;-) I don’t like Firefox, because in spite of all the plugins it can’t cope with all the useful features of Galeon 1.2.x or Opera. That’s the UI point of view.

But from the political (correctness) point of view, we have to ask ourself: What sage browser does the open source world still have?

Mozilla does not provide security patches, so Firefox, Mozilla (RIP), Epiphany and Galeon are no more acceptable for distribution use.
Konqueror has planed to drop KHTML in favor of Mozillas Gecko. So see above.
Dillo’s rendering engine is fast but not really state of the art. Same counts for glinks (aka “links -g”).
Lynx, links and w3m somehow don’t count since the distributions (and sometimes, me too ;-) primarily need a graphical web browser.

But back to usaility: I heard from quite a few people — even open source people — evaluating or even already using Opera as an alternative, because there is no sage open source web browser, even if you don’t count Mozillas security policy. And I can understand them. If Galeon wouldn’t exist, I probably would be a convinced Opera on Debian user myself, although Opera is closed source. But I and many more can’t live without a working and sage web browser.

The only thing, I don’t like with Opera is that this company seems to be (or at least was a few years ago) very chaotic and uncoordinated. (And I really wonder, how they are able to produce such impressive software.) But that’s another story…

Creative Toilet Paper Usage in Webcomics

abe+blog@deuxchevaux.org (Axel Beckert) — Wed, 21 Sep 2011 10:34:25 +0200

Funnily two of my daily web comics recently featured interesting things you could do with toilet paper: Zits on 19th of September 2011 involving a fan and Calvin and Hobbes on 13th of September 2011 involving flushing the toilet.

Although both experiments are obviously resource wasting, they look like quite some fun and I’m tempted to actually try them both at least once. (I though don’t plan to try this, too. :-)

192.168.noone.org

abe+blog@deuxchevaux.org (Axel Beckert) — Wed, 04 Nov 2009 10:48:29 +0100

About a year ago, Eric Poscher invented the IP address blog and installed his one at http://192.168.epe.at/. Every hour his netbook notes down the IP address of the interface which currenntly the default route goes through and if it has an internet connection, it uploads the list of IP adresses it had. Additionally, he filters the list to IP addresses in 192.168.0.0/16.

June this year he published the source code behind his IP blog under GPL and Creative Commons. I modified his script slighty to just write down the new IP address if it’s different to the previous one, but without any filter. This makes the list much more colorful (and my online times less traceable :-) as you can see at http://192.168.noone.org/.

But the biggest disadvantage of Eric’s code design is not the fact that it’s a (quite nice to read :-) shell script but that it doesn’t save the list of IPs separately and is not able to regenerate everything if you want to change the design, but always just adds a line to the HTML page.

So I rewrote the whole thing in Perl last Saturday while sitting the dog of my parents. If you change the templates and call the script again, it regenerates the whole list with the new templates. The code is also under GPL, the HTML parts are under Creative Commons, too.

And hey, this is one of the very few (if not only) applications which are much more fun with IPv4 than with IPv6. ;-)